Field of the Invention
The present invention relates to a novel process for producing a propionic acid derivative. More specifically, the present invention relates to a novel process for producing a 2-aralkyl-3-hydroxypropionic acid or its ester. The 2-aralkyl-3-hydroxypropionic acid can produce the optically active substance thereof through optical resolution with a resolving agent or an enzyme. This is convertible into an intermediate which is extremely important as a constituent of a lenin inhibitor (refer to J. Med. Chem. 1988, vol. 31, 1839 and WO 9116031), an enkephalinase inhibitor (refer to Japanese Patent Kokai Publication Nos. JP-A-2-161 and JP-A-8-59,606) or a protease inhibitor (refer to Japanese Patent Kohyou Publication No. JP-A-9-505,284).